Naturally occuring balata is the standard for golf ball covers and is the standard in processability and properties for substitutes therefor. Unfortunately balata is expensive, difficult to obtain and since it occurs naturally, it presents problems in lack of uniformity from batch to batch. Many substitutes for balata have been proposed for golf ball covers. Among them has been the polyesterurethane described in U.S. Pat. No. 3,034,791 wherein a golf ball cover is described that is the reaction product of 1 mol of polytetramethyleneether glycol, 2 mols of an isomeric mixture of toluene-2,4-diisocyanate, and about 25 percent of toluene 2,6-diisocyanate, with 16 weight parts of 4,4'- methylene-bis (2-chloroanaline) as a curing or cross-linking agent. This material, patented in 1962, has several disadvantages. First, the curing agent is a toxic material. Second, as taught in the Patent, the handling time for the reaction product of the diisocyanate-polytetramethyleneether glycol is critical and results in handling problems in processing. The patent teaches that when short aging times are used, the golf ball cover stock may have poor golf ball core centering and thread show-through. When long aging times are involved, cover penetration of the stocks into thread interstices is limited, resulting in poor cover adhesion, uneven compression, and the like. Improved materials for golf ball covers are an objective of this invention.